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<tr class="t-nv"><td colspan="5"> <strong class="selflink">Variable templates for type traits</strong></td></tr>
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<p>Version 1 of the C++ Extensions for Library Fundamentals provides a number of <code>constexpr</code> variable templates for type traits classes, as well as other similar class templates with public <code>::value</code> members.
</p><p>Unless otherwise noted, the following variable templates are defined in the <code>std::experimental</code> namespace.
</p>
<table class="t-dsc-begin">

<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Type_traits"> Type traits</span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Primary_type_categories">  Primary type categories </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/type_traits&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/type traits (page does not exist)">&lt;experimental/type_traits&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_void"></span><span id="is_void_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_void_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_void.html"><span class="kw456">std::<span class="me2">is_void</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_null_pointer"></span><span id="is_null_pointer_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_null_pointer_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_null_pointer.html"><span class="kw458">std::<span class="me2">is_null_pointer</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_integral"></span><span id="is_integral_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_integral_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_integral.html"><span class="kw462">std::<span class="me2">is_integral</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_floating_point"></span><span id="is_floating_point_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_floating_point_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_floating_point.html"><span class="kw464">std::<span class="me2">is_floating_point</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_array"></span><span id="is_array_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_array_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_array.html"><span class="kw466">std::<span class="me2">is_array</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_pointer"></span><span id="is_pointer_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_pointer_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_pointer.html"><span class="kw468">std::<span class="me2">is_pointer</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_lvalue_reference"></span><span id="is_lvalue_reference_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_lvalue_reference_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_lvalue_reference.html"><span class="kw470">std::<span class="me2">is_lvalue_reference</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_rvalue_reference"></span><span id="is_rvalue_reference_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_rvalue_reference_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_rvalue_reference.html"><span class="kw472">std::<span class="me2">is_rvalue_reference</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_member_object_pointer"></span><span id="is_member_object_pointer_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_member_object_pointer_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_member_object_pointer.html"><span class="kw474">std::<span class="me2">is_member_object_pointer</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_member_function_pointer"></span><span id="is_member_function_pointer_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_member_function_pointer_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_member_function_pointer.html"><span class="kw476">std::<span class="me2">is_member_function_pointer</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_enum"></span><span id="is_enum_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_enum_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_enum.html"><span class="kw478">std::<span class="me2">is_enum</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_union"></span><span id="is_union_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_union_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_union.html"><span class="kw480">std::<span class="me2">is_union</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_class"></span><span id="is_class_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_class_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_class.html"><span class="kw482">std::<span class="me2">is_class</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_function"></span><span id="is_function_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_function_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_function.html"><span class="kw484">std::<span class="me2">is_function</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Composite_type_categories">  Composite type categories  </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/type_traits&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/type traits (page does not exist)">&lt;experimental/type_traits&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_reference"></span><span id="is_reference_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_reference_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_reference.html"><span class="kw486">std::<span class="me2">is_reference</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_arithmetic"></span><span id="is_arithmetic_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_arithmetic_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_arithmetic.html"><span class="kw488">std::<span class="me2">is_arithmetic</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_fundamental"></span><span id="is_fundamental_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_fundamental_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_fundamental.html"><span class="kw490">std::<span class="me2">is_fundamental</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_object"></span><span id="is_object_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_object_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_object.html"><span class="kw492">std::<span class="me2">is_object</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_scalar"></span><span id="is_scalar_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_scalar_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_scalar.html"><span class="kw494">std::<span class="me2">is_scalar</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_compound"></span><span id="is_compound_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_compound_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_compound.html"><span class="kw496">std::<span class="me2">is_compound</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_member_pointer"></span><span id="is_member_pointer_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_member_pointer_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_member_pointer.html"><span class="kw498">std::<span class="me2">is_member_pointer</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Type_properties">  Type properties  </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/type_traits&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/type traits (page does not exist)">&lt;experimental/type_traits&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_const"></span><span id="is_const_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_const_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_const.html"><span class="kw500">std::<span class="me2">is_const</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_volatile"></span><span id="is_volatile_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_volatile_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_volatile.html"><span class="kw502">std::<span class="me2">is_volatile</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivial"></span><span id="is_trivial_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivial_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_trivial.html"><span class="kw504">std::<span class="me2">is_trivial</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_copyable"></span><span id="is_trivially_copyable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_copyable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_trivially_copyable.html"><span class="kw506">std::<span class="me2">is_trivially_copyable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_standard_layout"></span><span id="is_standard_layout_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_standard_layout_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_standard_layout.html"><span class="kw508">std::<span class="me2">is_standard_layout</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_pod"></span><span id="is_pod_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_pod_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_pod.html"><span class="kw510">std::<span class="me2">is_pod</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_literal_type"></span><span id="is_literal_type_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_literal_type_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_literal_type.html"><span class="kw512">std::<span class="me2">is_literal_type</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_empty"></span><span id="is_empty_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_empty_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_empty.html"><span class="kw514">std::<span class="me2">is_empty</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_polymorphic"></span><span id="is_polymorphic_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_polymorphic_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_polymorphic.html"><span class="kw516">std::<span class="me2">is_polymorphic</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_abstract"></span><span id="is_abstract_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_abstract_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_abstract.html"><span class="kw518">std::<span class="me2">is_abstract</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_final"></span><span id="is_final_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_final_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_final.html"><span class="kw460">std::<span class="me2">is_final</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_signed"></span><span id="is_signed_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_signed_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_signed.html"><span class="kw522">std::<span class="me2">is_signed</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_unsigned"></span><span id="is_unsigned_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_unsigned_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_unsigned.html"><span class="kw524">std::<span class="me2">is_unsigned</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>

</table>
<table class="t-dsc-begin">

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Supported_operations">  Supported operations  </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/type_traits&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/type traits (page does not exist)">&lt;experimental/type_traits&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_constructible"></span><span id="is_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_constructible.html"><span class="kw526">std::<span class="me2">is_constructible</span></span></a><span class="sy1">&lt;</span>T, Args...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_constructible"></span><span id="is_trivially_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_constructible.html"><span class="kw528">std::<span class="me2">is_trivially_constructible</span></span></a><span class="sy1">&lt;</span>T, Args...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_constructible"></span><span id="is_nothrow_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span>... <span class="me1">Args</span><span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_constructible.html"><span class="kw530">std::<span class="me2">is_nothrow_constructible</span></span></a><span class="sy1">&lt;</span>T, Args...<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_default_constructible"></span><span id="is_default_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_default_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_default_constructible.html"><span class="kw532">std::<span class="me2">is_default_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_default_constructible"></span><span id="is_trivially_default_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_default_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_default_constructible.html"><span class="kw534">std::<span class="me2">is_trivially_default_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_default_constructible"></span><span id="is_nothrow_default_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_default_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_default_constructible.html"><span class="kw536">std::<span class="me2">is_nothrow_default_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_copy_constructible"></span><span id="is_copy_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_copy_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_copy_constructible.html"><span class="kw538">std::<span class="me2">is_copy_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_copy_constructible"></span><span id="is_trivially_copy_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_copy_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_copy_constructible.html"><span class="kw540">std::<span class="me2">is_trivially_copy_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_copy_constructible"></span><span id="is_nothrow_copy_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_copy_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_copy_constructible.html"><span class="kw542">std::<span class="me2">is_nothrow_copy_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_move_constructible"></span><span id="is_move_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_move_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_move_constructible.html"><span class="kw544">std::<span class="me2">is_move_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_move_constructible"></span><span id="is_trivially_move_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_move_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_move_constructible.html"><span class="kw546">std::<span class="me2">is_trivially_move_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_move_constructible"></span><span id="is_nothrow_move_constructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_move_constructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_move_constructible.html"><span class="kw548">std::<span class="me2">is_nothrow_move_constructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_assignable"></span><span id="is_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_assignable.html"><span class="kw550">std::<span class="me2">is_assignable</span></span></a><span class="sy1">&lt;</span>T, U<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_assignable"></span><span id="is_trivially_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_assignable.html"><span class="kw552">std::<span class="me2">is_trivially_assignable</span></span></a><span class="sy1">&lt;</span>T, U<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_assignable"></span><span id="is_nothrow_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_assignable.html"><span class="kw554">std::<span class="me2">is_nothrow_assignable</span></span></a><span class="sy1">&lt;</span>T, U<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_copy_assignable"></span><span id="is_copy_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_copy_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_copy_assignable.html"><span class="kw556">std::<span class="me2">is_copy_assignable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_copy_assignable"></span><span id="is_trivially_copy_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_copy_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_copy_assignable.html"><span class="kw558">std::<span class="me2">is_trivially_copy_assignable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_copy_assignable"></span><span id="is_nothrow_copy_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_copy_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_copy_assignable.html"><span class="kw560">std::<span class="me2">is_nothrow_copy_assignable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_move_assignable"></span><span id="is_move_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_move_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_move_assignable.html"><span class="kw562">std::<span class="me2">is_move_assignable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_move_assignable"></span><span id="is_trivially_move_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_move_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_move_assignable.html"><span class="kw564">std::<span class="me2">is_trivially_move_assignable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_move_assignable"></span><span id="is_nothrow_move_assignable_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_move_assignable_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_move_assignable.html"><span class="kw566">std::<span class="me2">is_nothrow_move_assignable</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_destructible"></span><span id="is_destructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_destructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_destructible.html"><span class="kw568">std::<span class="me2">is_destructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_trivially_destructible"></span><span id="is_trivially_destructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_trivially_destructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_destructible.html"><span class="kw570">std::<span class="me2">is_trivially_destructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_nothrow_destructible"></span><span id="is_nothrow_destructible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_nothrow_destructible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_destructible.html"><span class="kw572">std::<span class="me2">is_nothrow_destructible</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="has_virtual_destructor"></span><span id="has_virtual_destructor_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> has_virtual_destructor_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/has_virtual_destructor.html"><span class="kw582">std::<span class="me2">has_virtual_destructor</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>

</table>
<table class="t-dsc-begin">

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Property_queries">  Property queries  </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/type_traits&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/type traits (page does not exist)">&lt;experimental/type_traits&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="alignment_of"></span><span id="alignment_of_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <a href="../types/size_t.html"><span class="kw106">std::<span class="me2">size_t</span></span></a> alignment_of_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/alignment_of.html"><span class="kw584">std::<span class="me2">alignment_of</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="rank"></span><span id="rank_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <a href="../types/size_t.html"><span class="kw106">std::<span class="me2">size_t</span></span></a> rank_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/rank.html"><span class="kw586">std::<span class="me2">rank</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="extent"></span><span id="extent_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw4">unsigned</span> I <span class="sy1">=</span> <span class="nu0">0</span><span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <a href="../types/size_t.html"><span class="kw106">std::<span class="me2">size_t</span></span></a> extent_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/extent.html"><span class="kw588">std::<span class="me2">extent</span></span></a><span class="sy1">&lt;</span>T, I<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Type_relationships">  Type relationships  </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/type_traits&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/type traits (page does not exist)">&lt;experimental/type_traits&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_same"></span><span id="is_same_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> U<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_same_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_same.html"><span class="kw590">std::<span class="me2">is_same</span></span></a><span class="sy1">&lt;</span>T, U<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_base_of"></span><span id="is_base_of_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Base, <span class="kw1">class</span> Derived<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_base_of_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_base_of.html"><span class="kw592">std::<span class="me2">is_base_of</span></span></a><span class="sy1">&lt;</span>Base, Derived<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_convertible"></span><span id="is_convertible_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> From, <span class="kw1">class</span> To<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_convertible_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../types/is_convertible.html"><span class="kw594">std::<span class="me2">is_convertible</span></span></a><span class="sy1">&lt;</span>From, To<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr>
<td colspan="2"> <h3> <span class="mw-headline" id="Other_variable_templates"> Other variable templates </span></h3>
</td></tr>

<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="std::ratio_comparison">  <span class="t-lc"><a href="../numeric/ratio/ratio.html" title="cpp/numeric/ratio/ratio">std::ratio</a></span> comparison  </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/ratio&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/ratio (page does not exist)">&lt;experimental/ratio&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="ratio_equal"></span><span id="ratio_equal_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R1, <span class="kw1">class</span> R2<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> ratio_equal_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../numeric/ratio/ratio_equal.html"><span class="kw1548">std::<span class="me2">ratio_equal</span></span></a><span class="sy1">&lt;</span>R1, R2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="ratio_not_equal"></span><span id="ratio_not_equal_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R1, <span class="kw1">class</span> R2<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> ratio_not_equal_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../numeric/ratio/ratio_not_equal.html"><span class="kw1550">std::<span class="me2">ratio_not_equal</span></span></a><span class="sy1">&lt;</span>R1, R2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="ratio_less"></span><span id="ratio_less_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R1, <span class="kw1">class</span> R2<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> ratio_less_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../numeric/ratio/ratio_less.html"><span class="kw1552">std::<span class="me2">ratio_less</span></span></a><span class="sy1">&lt;</span>R1, R2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="ratio_less_equal"></span><span id="ratio_less_equal_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R1, <span class="kw1">class</span> R2<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> ratio_less_equal_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../numeric/ratio/ratio_less_equal.html"><span class="kw1554">std::<span class="me2">ratio_less_equal</span></span></a><span class="sy1">&lt;</span>R1, R2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="ratio_greater"></span><span id="ratio_greater_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R1, <span class="kw1">class</span> R2<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> ratio_greater_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../numeric/ratio/ratio_greater.html"><span class="kw1556">std::<span class="me2">ratio_greater</span></span></a><span class="sy1">&lt;</span>R1, R2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="ratio_greater_equal"></span><span id="ratio_greater_equal_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> R1, <span class="kw1">class</span> R2<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> ratio_greater_equal_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../numeric/ratio/ratio_greater_equal.html"><span class="kw1558">std::<span class="me2">ratio_greater_equal</span></span></a><span class="sy1">&lt;</span>R1, R2<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr>
<td colspan="2"> <h5> <span class="mw-headline" id="Miscellaneous">  Miscellaneous </span></h5>
</td></tr>

<tr class="t-dsc-hitem">
<td>  Variable template
</td>
<td>  Value
</td></tr>


<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/tuple&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/tuple (page does not exist)">&lt;experimental/tuple&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="tuple_size"></span><span id="tuple_size_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <a href="../types/size_t.html"><span class="kw106">std::<span class="me2">size_t</span></span></a> tuple_size_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../utility/tuple/tuple_size.html"><span class="kw1104">std::<span class="me2">tuple_size</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/chrono&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/chrono (page does not exist)">&lt;experimental/chrono&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="treat_as_floating_point"></span><span id="treat_as_floating_point_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> Rep<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> treat_as_floating_point_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../chrono/treat_as_floating_point.html"><span class="kw1006">std::<span class="me2">chrono</span><span class="sy4">::</span><span class="me2">treat_as_floating_point</span></span></a><span class="sy1">&lt;</span>Rep<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span><sup>[1]</sup>
</td></tr>



<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/system_error&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/system error (page does not exist)">&lt;experimental/system_error&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_error_code_enum"></span><span id="is_error_code_enum_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_error_code_enum_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../error/error_code/is_error_code_enum.html"><span class="kw879">std::<span class="me2">is_error_code_enum</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_error_condition_enum"></span><span id="is_error_condition_enum_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_error_condition_enum_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../error/error_condition/is_error_condition_enum.html"><span class="kw876">std::<span class="me2">is_error_condition_enum</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="../header/experimental/functional.html" title="cpp/header/experimental/functional">&lt;experimental/functional&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="is_bind_expression"></span><span id="is_bind_expression_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> is_bind_expression_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../utility/functional/is_bind_expression.html"><span class="kw1058">std::<span class="me2">is_bind_expression</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>


<tr class="t-dsc">
<td>  <span id="is_placeholder"></span><span id="is_placeholder_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">int</span> is_placeholder_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../utility/functional/is_placeholder.html"><span class="kw1059">std::<span class="me2">is_placeholder</span></span></a><span class="sy1">&lt;</span>T<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>



<tr class="t-dsc-header">
<td colspan="2"> <div>Defined in header <code><a href="https://en.cppreference.com/mwiki/index.php?title=cpp/header/experimental/memory&amp;action=edit&amp;redlink=1" class="new" title="cpp/header/experimental/memory (page does not exist)">&lt;experimental/memory&gt;</a></code> </div>
</td></tr>

<tr class="t-dsc">
<td>  <span id="uses_allocator"></span><span id="uses_allocator_v"></span><span class="mw-geshi cpp source-cpp"><span class="kw1">template</span> <span class="sy1">&lt;</span><span class="kw1">class</span> T, <span class="kw1">class</span> Alloc<span class="sy1">&gt;</span> <span class="kw4">constexpr</span> <span class="kw4">bool</span> uses_allocator_v <span class="sy1">=</span></span>
</td>
<td>  <span class="mw-geshi cpp source-cpp"><a href="../memory/uses_allocator.html"><span class="kw705">std::<span class="me2">uses_allocator</span></span></a><span class="sy1">&lt;</span>T, Alloc<span class="sy1">&gt;</span><span class="sy4">::</span><span class="me2">value</span><span class="sy4">;</span></span>
</td></tr>

</table>
<h3><span class="mw-headline" id="Notes"> Notes </span></h3>
<p>[1]: Defined in the <code>std::chrono::experimental</code> namespace.
</p>
<!-- 
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Post‐expand include size: 121657/2097152 bytes
Template argument size: 40975/2097152 bytes
Highest expansion depth: 14/40
Expensive parser function count: 0/100
-->

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